(a) Field of the Invention
This invention relates to exposure controlling device for cameras and more particularly to a program exposure controlling device by a TTL light measurement adapted to cameras of a type using interchangeable photographing lenses.
(b) Description of the Prior Art
There is already known a camera which can use interchangeable photographing lenses and of a type in which a TTL light measurement is made under the maximum diaphragm aperture and, on the basis of the result, a combination of a proper diaphragm aperture and shutter speed (exposure time) can be programmatically controlled. However, according to the conventional exposure controlling system adapted to this kind of camera, the range of selection of diaphragm values to be controlled is so wide that here have been defects that the entire controlling mechanism will be complicated and, as a result, the camera can not help becoming expensive.